Non-tilt mixer and blade means therefor

ABSTRACT

A non-tilt mixer comprises a drum supported on and reversely rotatable about its horizontal axis (for mixing and then discharge) by means of pneumatically-tired wheels. The drum comprises a cylindrical center section and conical end sections and has an inlet opening at one end and a discharge opening at its other end. The drum is provided on its interior with a plurality of flat mixer blades secured to the inside of the cylindrical center section and with a plurality of curved or scoop-like discharge blades secured to the inside of the conical section at the discharge end of the drum. Each discharge blade extends between and partially overlaps an adjacent pair of mixer blades. Each discharge blade defines a scoop or chute which is operable when the drum rotates in the discharge direction to discharge through the discharge opening of the drum. The discharge blades are arranged and connected so that the several chutes converge and discharge at the center of the discharge opening.

United States Patent [1 1 Albin et a1.

[4 1 Oct. 28, 1975 NON-TILT MIXER AND BLADE MEANS THEREFOR [75]Inventors: Max D. Albin; James R. Clabaugh,

both of Urbana; Luis G. Manero, Champaign, all of 111.

[73] Assignee: Koehring Company, Milwaukee,

Wis.

[22] Filed: May 28, 1974 [21] Appl. No.: 473,330

[52] US. Cl 259/177 R; 259/3; 259/30 [51] Int. Cl. B28C 5/20 [58] Fieldof Search 259/177- R, 3, 30,57, 175,

FOREIGN PATENTS OR APPLICATIONS Belgium 259/177 Attorney, Agent, orFirmAndrew .1. Beck [5 7 ABSTRACT A non-tilt mixer comprises a drumsupported on and reversely rotatable about its horizontal axis (formixing and then discharge) by means of pneumaticallytired wheels. Thedrum comprises a cylindrical center section and conical end sections andhas an inlet opening at one end and a discharge opening at its otherend. The drum is provided on its interior with a plurality of flat mixerblades secured to the inside of the cylindrical center section and witha plurality of curved or scoop-like discharge blades secured to theinside of the conical section at the discharge end of the drum. Eachdischarge blade extends between and partially overlaps an adjacent pairof mixer blades. Each discharge blade defines a scoop or chute which isoperable when the drum rotates in the discharge direction to dischargethrough the discharge opening of the drum. The discharge blades arearranged and connected so that the several chutes converge and dischargeat the center of the discharge opening.

5 Claims, 12 Drawing Figures US. Patent Oct.28, 1975 Sheet10f4 3,915,439

U.S. Patent Oct.28, 1975 Sheet 2 of4 3,915,439

US. Patent Oct. 28, 1975 Sheet 3 of4 3,915,439

US. Patent' Oct. 28, 1975 Sheet 4 of4 3,915,439

FIG.1O

NON-TILT MIXER AND BLADE MEANS THEREFOR BACKGROUND OF THE INVENTION 1.Field of Use This invention relates generally to non-tilt reverselyrotatable mixers, such as are usedwith concrete batch plants, andparticularly to mixing and discharge blade means inthe drum thereof.

2. Description of the Prior Art U.S. Pat. No. 3,016,232, issued Jan. 9,1962 to Domenighetti for Mixer Driven and Supported by Wheels ofFlexible Material, discloses a mixer having a drum reversely rotatableabout a horizontal axis, inlet and discharge openings in conical endsections at opposite ends of the drum, two spaced apart rollerassemblies including pneumatic tired wheels for supporting the drum andfor rotating the drum in opposite directions (one way for mixing and theopposite way for discharge), means for driving the shaft of both rollerassemblies, and a pair of axially spaced apart auxiliary rollers actingon the drum to prevent axial drum movement. The prior art also disclosesa wide variety of blade configurations and arrangements in mixers ofvarious kinds. For example, Pat. No. 3,258,253 shows a drum type mixer(rotatable in one direction only) having a set of bracket-supportedmixer blades near the inlet end of the drum, which blades are angularlyoffset from the axis of drum rotation. Pat. No. 3,258,253 also shows aset of bucket blades near the outlet end of the drum. British Patent328,895 shows flat blades near the inlet and curved blades near theoutlet of a drum. However, the prior art does not disclose blade shapesor blade arrangements of the same type as in the subject mixer.

SUMMARY OF THE INVENTION In accordance with the present invention, thereis provided a non-tilt concrete mixer for use, for example, with aconcrete batch plant and comprising a horizontally disposed reverselyrotatable drum and means for driving or rotating the drum in oppositedirections about its horizontal axis. The drum, which comprises agenerally cylindrical center section and conical end sections with aninlet opening in the conical section at one end and a discharge openingin the conical section at the other end, is supported on and reversablydrivable or rotatable about its horizontal axis (for mixing anddischarge purposes) by means of a support and drive assembly. Theassembly comprises a pair of parallel spaced apart rotatable shafts (atleast one of which is driven by an electric or hydraulic motor) and eachshaft has two spaced apart sets of pneumatically tired wheels mountedthereon for rotation therewith. Each set comprises one or more wheelswhich engage the exterior surface of the cylindrical section of the drumand each set nearest the drum inlet end comprises a greater number ofwheels than the set nearest the drum outlet end. Roller means engageopposite ends of the cylindrical center section of the drum to preventaxial movement of the drum as it rotates. The generally conical inletand outlet end sections of the drum are provided with inlet anddischarge openings at the centers of the conical inlet and outlet endsections, respectively. The drum rotates about its axis in one directionfor mixing purposes and in an opposite direction 'for dischargepurposes. A plurality (preferably three or four) or spaced apart mixingblades are mounted on the inside of the cylindrical section of the drum.Each mixer blade is flat and is supported on a pair of spaced apartbrackets on a cylindrical mid-portion of the drum, with its lower edgespaced from the drum wall and with its leading edge offset from the axisof drum rotation in the mixing direction so that its planar surfacesdefine an angle of about 12 with the drum axis. A plurality (preferablythree or four) of spaced apart discharge blades are mounted on theinside of the conical discharge end section of the drum. Each dischargeblade is disposed intermediately of an adjacent pair of mixer blades andextends partially therebetween in overlapping relationship thereto. Eachdischarge blade, which is preferably fabricated of three blade sections,is scoop-like and defines a chute dischargeable through the dischargeopening of the drum. The plurality of discharge blades are arranged andconnected to the drum and to each other so that all of the chutesconverge near the center of said discharge opening. The discharge bladesoperate to discharge material being mixed in the drum only when the drumrotates in one direction.

A mixer having blades and blade arrangements in accordance with theinvention affords several advantages over prior art arrangements. Forexample, the converging or concentric arrangement of the severaldischarge chutes concentrates the mix being discharged into a smallerstream, thereby reducing spillage and waste as the mixer discharges. Theoverlapped arrangement of the mixer and discharge blades causes themixer blades to feed the discharge blades during discharge rotation. Thedischarge blade arrangement is extremely strong and can handle heavyloads, as the blades are supported not only on the drum but by eachother. The mixer and discharge blades are relatively easy andinexpensive to fabricate, install and replace when worn. Furthermore,the discharge blades, although defining scoops or chutes of a complexshape which facilitates neat and complete discharge from the drum, areactually formed of flat blade sections cut from sheet metal and do notrequire complex dies or special presses during fabrication.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a cementmixer in accordance with the invention shown associated with portions ofa concrete batch plant;

FIG. 2 is an elevation view of the exterior of the discharge end of themixer shown in FIG. 1 with parts broken away to show details;

FIG. 3 is an enlarged view, partly in section, of the mixer drum takenon line 33 of FIG. 2;

FIG. 4 is a view of the interior of the discharge end of the mixer drumtaken on line 44 of FIG. 3;

FIG. 5 is an enlarged view similar to FIG. 4 of the discharge end ofanother embodiment of four-bladed mixer drum in accordance with theinvention;

FIG. 6 is an enlarged view similar to FIG. 2 of the blade arrangementshown in FIG. 5;

FIG. 7 is an enlarged perspective view taken from the discharge end ofthe drum and showing one discharge blade of the mixer shown in FIGS. 1,2, 3 and 4;

FIG. 8 is a plan view of a blank for one blade section for the dischargeblade shown in FIG. 7 prior to bending and forming thereof;

FIG. 9 is an end view of the blade taken on line 9-9 of FIG. 8 after itis bent to shape;

FIG. is a plan view of a first fillet plate shown in FIG. 7;

FIG. 11 is a plan view of a second fillet plate shown in FIG. 7; and

FIG. 12 is a perspective view. similar to FIG. 7, of one discharge bladeassembly comprising the blade and fillets shown in FIGS. 7 through 11.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, thereis provided a nontilt concrete mixer 10 for use, for example, with aconcrete batch plant which, for example, includes a feed hopper 11 and adischarge chute 12. Mixer 10 comprises a horizontally disposed reverselyrotatable drum 14 and means for driving or rotating the drum in oppositedirections about its horizontal axis 15. The drum 14, which comprises agenerally cylindrical center section 16 and conical end sections 17 and18, with an inlet opening 20 in the conical section at the drum inletend and a discharge opening 21 in the conical section at the drumdischarge end, is supported on reversably drivable or rotatable aboutits horizontal axis 15 (in the direction of arrow 22 for mixing and inthe direction of arrow 23 for discharge) by means of a support and driveassembly. The assembly comprises a pair or paral lel spaced apartrotatable shafts supported on a frame 24 as by bearings 31. At least oneshaft 25 is driven by an electric or hydraulic motor 26, and each shaft25 has two spaced apart sets 28 and 29 of pneumatically tired wheels 27mounted thereon for rotation therewith. Each set 28 and 29 comprises oneor more wheels 27 which engage the exterior surface of the cylindricalsection of the drum 14 and each set 28 nearest the drum inlet endcomprises a greater number of wheels than the set 29 nearest the drumoutlet end. Roller means 30 engage opposite ends of the cylindricalcenter section 16 of the drum 14 to prevent axial movement of the drumas it rotates. The generally conical inlet and outlet end sections 17and 18 of the drum 14 are provided with inlet and discharge openings 20and 21, respectively, at the centers of the conical inlet and outlet endsections 17 and 18, respectively. The drum 14 rotates about its axis 15in one direction (arrow 22) for mixing purposes and in an oppositedirection (arrow 23) for discharge purposes. As FIGS. 3 and 4 show, aplurality (three) of spaced apart mixing blades 34 are mounted on theinside of the cylindrical section 16 of the drum 14. Each mixer blade 34is flat and is supported as by welding, on a pair of spaced apartbrackets 37 which are connected as by welding to the inside ofcylindrical section 16 of the drum 14, with the lower edge 38 of eachblade 34 being spaced from the drum wall and with the leading edge 39 ofeach blade 34 being offset from the axis 15 of drum rotation in themixing direction so that the planar surfaces 42 of blade 34 define anangle of about 12 with the drum axis. as FIG. 1 shows. As FIGS. 2, 3 and4 show, a plurality (three) of spaced apart discharge blades 50 aremounted on the inside of the conical discharge end section 18 of thedrum 14. Each discharge blade 50 is disposed intermediately of anadjacent pair of mixer blades 34 and extends partially therebetween inoverlapping relationship thereto, as FIG. 3 shows. Each discharge blade50, as FIGS. 7 through 12 show, is preferably fabricated of three bladesections, 52, 54, 56, is scoop-like and defines a chute 60 dischargeablethrough the discharge opening 21 of the drum 14. The

plurality of discharge blades 50 are arranged and con- 4 nected to thedrum 14 and to each other so that all of the chutes 60 converge near thecenter of discharge opening 21. The discharge blades operate todischarge material being mixed in the drum only when the drum rotates inone direction, i.e. in the direction of arrow 23.

The converging or concentric arrangement of the several discharge chutes60 concentrates the mix being discharged through opening 21 into asmaller stream, thereby reducing the possibility of spillage and wasteas the mixer 10 discharges into chute 12. The overlapped arrangement ofthe mixer blades 34 and the discharge blades 50 causes the mixer blades34 to feed the discharge blades 50 during discharge rotation in thedirection of arrow 23. The discharge blade arrangement is extremelystrong and can handle heavy loads, as the blades 50 are supported notonly on the drum 14, as by welding at 61, but by each other, as bywelding at 75. The mixer blades and the discharge blades 50 arerelatively easy and inexpensive to fabricate, install and replace whenworn. Furthermore, the discharge blades 50, although defining scoops orchutes 60 of a complex shape which facilitates neat and completedischarge from the drum 14, are each actually formed of blade sections52, 54 and 56 cut from sheet metal and initially flat and, therefore, donot require complex dies or special presses during fabrication.

Referring to FIGS. 7 through 12, each discharge blade 50 comprises amain blade section 52 and fillet means formed of two flat blade sections54 and 56 joined by welding as at 73. Main blade section 52, which isinitially flat, is bent along fold lines 66 and 67 and cooperates withthe fillet means to define side walls of the chute 60. Main bladesection 52 has an edge 61 connected to the inside surface of drum 14 asby welding at 62. Edge 61 comprises two curved edge portions 61A and 61Bwhich conform to the shapes of conical drum section 18 and cylindricaldrum section 16, respectively. Main blade section 52 also has a freeedge 64. The fillet means is connected, as by welding at 63 and 65, toand between the inside surface of drum l4 and the scooping surface ofmain blade section 52. Section 54 of the fillet has an edge 69conforming to the shape of conical drum section 18. Section 56 of thefillet has an edge 68 conforming to the shape of cylindrical drumsection 16. Main blade section 52 of discharge blade 50 is provided witha discharge end 74 or edge which is connected as by welding at 75 to andbetween the corresponding edges of a pair of adjacent discharge blades50.

Referring to FIGS. 5 and 6, there is shown another embodiment of a mixer10A in accordance with the invention having a drum 14A similar in allrespects and in mode of operation to drum 14 hereinbefore described,except that drum 14A comprises four mixer blades 34A and four dischargeblades 50A and is especially well adapted for handling a larger quantityof mix than mixer 10 hereinbefore described, i.e., for example, 2 cubicyards as compared to 1 cubic yard. Each mixer blade 50A comprises a mainblade section 52A, and a two blade section 54A and 56A forming a filletwhich cooperates with section 52A to define a chute 60A.

OPERATION Mixer 10 operates in the following manner. it being understoodthat mixer 10A would operate in substantially the same manner. A batchof cement and aggregate (including sand) and necessary water isdeposited in chute 11 and from there through opening 20 into theinterior of drum 14. Drum 14 rotates in the mixing direction, i.e. inthe direction of arrow 22, by means of motor 26 which drives shaft 25 tocause rotation of the wheels 27 on the driven shaft in the appropriatedirection. Since the load in drum 14 is heaviest at the inlet end of thedrum, it is preferable to provide a set of wheels comprising a greaternumber of wheels 27 than at the opposite end of the drum. Preferably,drum 14 is rotating in the mixing direction as the load of mix is beingsupplied thereto. As drum 14 rotates in the mixing direction mixing isaccomplished by means of the mixing blades 34. The space between thelower edge 38 of each mixing blade 34 enables passage of water and theslurry as the drum rotates. Since the drum 14 is rotating in the mixingdirection (arrow 22) the chutes 60 defined by the discharge blades 50are unable to scoop up and discharge any of the mix. After drum 14 hasbeen rotated sufficiently to effect proper mixing, the

direction of drum rotation is reversed so that the drum rotates in thedischarge direction (arrow 23) to effect discharge of the mix throughthe chutes 60 and through discharge I opening 21 into the dischargechute .12. When the drum 14 is rotating in the discharge directionangular disposition of the mixing blades 34, each of which extendsbetween and overlaps a pair of adjacent discharge blades 50, causes mixto be channelled toward the chutes 60 defined by the discharge blades50. In addition, the discharge blades 50 tend to scoop up mix from thebottom of the drum 14. The mix being scooped up by each chute 60 iscaused by gravity to slide downwardly and outwardly through dischargeopening 21 in drum 14 as the chute 60 rotates from the downwarddisposition shown in FIG. 3 and past a horizontal position toward thesloped position shown in the uppermost portion of FIG. 3. Thearrangement and configuration of the mixing blades 34 and the dischargeblades 50 is such that substantially all of the mix contained in drum 14is fed outwardly of the drum through discharge opening 21 by means ofthe discharge blades 50. As hereinbefore explained, a portion of eachdischarge blade 50 extends into and is secured to the cylindricalportion 16 of drum 14. In this manner the drum is completely emptiedduring the discharge process. As hereinbefore explained, the drum 14A ofmixer A operates in substantially the same manner as mixer 10. However,since drum 10A has a larger total capacity than mixer 10 it ispreferable that each mixer blade 34A and each discharge blade 50A handlea proportionately larger amount of the total mix. It is to be understoodfurther that the mixer drum 14A is mounted and driven in the same manneras drum 14.

We claim:

1. In a mixer: a drum rotatable about a horizontal axis and comprising acylindrical center section and end sections, one end section beingprovided with an inlet opening and the other end section being a conicaldischarge section and provided with a centrally located dischargeopening, means for supporting and for rotating said drum about its axisin one direction for mixing and in an opposite direction for discharge,a plurality of spaced apart flat mixing blades mounted on but spacedfrom the inside of said cylindrical section of said drum, each mixingblade being angularly offset from the axis of drum rotation, and aplurality of spaced apart discharge blades mounted on the inside of saidconical discharge section of said drum, each discharge blade beingdisposed intermediately of an adjacent pair of mixer blades andextending partially therebetween in overlapping relationship thereto,each discharge blade defining a chute discharge through said dischargeopening of said drum, each chute being located on the side of the bladein the direction in whic said drum rotates during discharge, each ofsaid plurality of discharge blades being arranged and connected to theinside of said conical discharge section and to adjacent dischargeblades so that all of said chutes converge near the center of saiddischarge opening, each discharge blade comprising a main blade sectionand fillet means, said main blade section having one edge connected tosaid conical discharge section and a bent free edge defining a side ofsaid chute, said fillet means being connected to and between saidconical discharge section and said main blade section and defininganother side of said chute, each main blade section having a dischargeend connected to the discharge ends of the adjacent discharge blades.

2. A mixer according to claim 1 wherein each of said fillet meanscomprises two blade sections which are connected to each other.

3. A mixer according to claim 2 wherein said two blade sections are flatand wherein siad main blade section is generally fiat but is providedwith an upturned free edge.

4. A mixer according to claim 1 wherein said means for supporting androtating said drum comprises a pair of horizontally spaced apart shafts,a pair of spaced apart sets of pneumatically-tired wheels on each shaft,each set comprising at least one of said wheels, and means forselectively driving at least one set of wheels on at least one of saidshafts to effect rotation of said drum in a desired direction.

5. A mixer according to claim 4 wherein each set of wheels closest tosaid inlet opening of said drum comprises a greater number of wheelsthan the set of wheels closest to said discharge opening.

1. In a mixer: a drum rotatable about a horizontal axis and comprising acylindrical center section and end sections, one end section beingprovided with an inlet opening and the other end section being a conicaldischarge section and provided with a centrally located dischargeopening, means for supporting and for rotating said drum about its axisin one direction for mixing and in an opposite direction for discharge,a plurality of spaced apart flat mixing blades mounted on but spacedfrom the inside of said cylindrical section of said drum, each mixingblade being angularly offset from the axis of drum rotation, and aplurality of spaced apart discharge blades mounted on the inside of saidconical discharge section of said drum, each discharge blade beingdisposed intermediately of an adjacent pair of mixer blades andextending partially therebetween in overlapping relationship thereto,each discharge blade defining a chute dischargeable through saiddischarge opening of said drum, each chute being located on the side ofthe blade in the direction in which said drum rotates during discharge,each of said plurality of discharge blades being arranged and connectedto the inside of said conical discharge section and to adjacentdischarge blades so that all of said chutes converge near the center ofsaid discharge opening, each discharge blade comprising a main bladesection and fillet means, said main blade section having one edgeconnected to said conical discharge section and a bent free edgedefining a side of said chute, said fillet means being connected to andbetween said conical discharge section and said main blade section anddefining another side of said chute, each main blade section having adischarge end connected to the dIscharge ends of the adjacent dischargeblades.
 2. A mixer according to claim 1 wherein each of said filletmeans comprises two blade sections which are connected to each other. 3.A mixer according to claim 2 wherein said two blade sections are flatand wherein said main blade section is generally flat but is providedwith an upturned free edge.
 4. A mixer according to claim 1 wherein saidmeans for supporting and rotating said drum comprises a pair ofhorizontally spaced apart shafts, a pair of spaced apart sets ofpneumatically-tired wheels on each shaft, each set comprising at leastone of said wheels, and means for selectively driving at least one setof wheels on at least one of said shafts to effect rotation of said drumin a desired direction.
 5. A mixer according to claim 4 wherein each setof wheels closest to said inlet opening of said drum comprises a greaternumber of wheels than the set of wheels closest to said dischargeopening.